Over one-third of US adolescents are obese or overweight, and large racial/ethnic disparities exist in obesity/ overweight rates. In the racially/ethnically diverse Los Angeles Unified School District (LAUSD), the second largest US school district and the community partner for this application, obesity and overweight prevalence (46%) is higher than the national average, und Black and Latino students have the highest prevalence. We have partnered with LUUSD to translate obesity policy into practice through NlMHD's R24 community-based participatory research (CBPR) Planning and Intervention Grants, for which we developed, pilot tested, and conducted a randomized controlled trial of our middle-school-based obesity prevention intervention, Students for Nutrition and exercise (SNaX). In this Dissemination Phase application, we seek funds to transition the intervention from research to practice. SNaX is a multi-level intervention that includes changes to the school food environment (e.g., sliced fruit and vegetable offerings; informational signage; free water at lunchtime), peer advocacy, and school-wide multimedia promotion. Our RCT results showed that SNaX is both effective at increasing healthy eating and cost-effective, and thus meets criteria as an evidence-based program worthy of dissemination. The specific aims are to use a theory-driven strategy and CBPR principles: 1) to synthesize and disseminate information about adolescent obesity prevention in general and SNaX in particular to community and academic stakeholders; 2) to enhance the general organizational and program- specific capacity of LAUSD to implement SNaX and maintain delivery of SNaX beyond the project period; 3) to disseminate and implement the SNaX program in LAUSD middle schools; and 4) to evaluate the SNeX dissemination and implementation process, including the domains of program reach, recruitment, efficacy, adoption, retention, implementation fidelity, and maintenance. We plan to use an iterative process, in which we initially launch dissemination in LAUSD's North region. We will evaluate and refine the dissemination process using a validated framework that includes program facility checklists, debriefing interviews with staff and students, and analyses of cafeteria records and physical fitness data. After the dissemination test, LAUSD plans to implement SNaX in middle schools across the rest of the district. Ultimately, we intend to find ways to disseminate SNaX more broadly, using lessons learned from the LAUSD dissemination process to guide entry into other school districts. Our goal is to bring obesity prevention out of the research realm and into communities, and thereby achieve enduring real-world changes in public health through the reduction and eventual elimination of disparities.